The present invention relates to a recording/reproducing apparatus for conducting recording or reproducing, in particular to that enabling to record a large amount or volume of data information, etc., at super-high density.
In communication systems and/or computer networks, etc., within an advanced information-oriented society in recent years, an amount of data increases rapidly, every year, to be used in the computers, in particular, accompanying with the widely broadening of the Internet broadband. And, accompanying with this, requirements also rise up, quickly, in particular, for the recording/reproducing apparatuses of large capacity and at high speed thereof.
As the technology for achieving the recording of data at high density, also being random-accessible, in relation to the conventional art, there are already known the followings; such as, a magnetic recording, an optical recording, and a semiconductor memory, etc., for example. In the field of the semiconductor memory, integration is improved in the degree thereof, every year; however, because of the problems, such as, the manufacturing technology or the like, for example, a semiconductor memory cannot be obtained, yet, that can satisfy the requirement of such large recording capacity of data (i.e., being equal or greater than 3 GB).
Also, in the magnetic recording and the optical recording, for achieving the information recording of such the large amount or capacity thereof, it is necessary to narrow a recording area to be small, so as to increase the recording density thereof. In the magnetic recording, an increase of recording density is remarkable due to the development of the magnetic head of GMR (Gigantic Magnetic Resistance effect), etc., but because of the problem on sensitivity of the reproducing head, it is difficult to obtain a unitary recording area being equal or less than 100 nm. Also in the optical recording, even if developing a semiconductor laser of wavelength 500 nm, for example, but it is a limit of diffraction of a light; therefore, it is said that the recording area being equal or less than 100 nm cannot be achieved.
On the other hand, developments are made on a scanning-type tunnel microscope (hereinafter, “STM”) and/or an atomic force microscope (hereinafter, “AFM”), having spatial resolution of level of atoms and molecules, and they are applied in various analyses on fine structures; i.e., being utilized widely as a surface analyzing apparatus. In particular, the AFM is developed to be a scanning-type probe microscope (hereinafter, “SPM”), using various kinds of physical quantities as a probe, in recent years, and lately, various studies are made upon the possibility of realization of a recording/reproducing apparatus with using those means; i.e., as a means for accessing to atoms and molecules.
In the recording/reproducing apparatus with using a cantilever, to be used in the AFM or the like, as is described in the following Patent Document 1, for example, information is recorded and/or deleted due to charge transfer or reversal of electric polarization within a predetermined area on surface of the recording medium, through applying voltage by means of a head, which is made from a stylus-like electrode. And, reproduction of information recorded in this predetermined area is performed, by detecting an amount of change on the electric charge, the electrostatic charge or the surface potential, or alternately, the differentiated amount of change thereof, under the condition that the head is in non-contact with the recording medium, with an aid of a frequency change, which is caused at the time when the cantilever is vibrated while applying voltage between the cantilever and the recording medium. Since the information can be reproduced under the condition of non-contact, in this manner, therefore, the head of the stylus-like electrode and/or the recording medium can be escaped or protected from abrasion, i.e., being worn away.
Also, when writing or recording is done by only one (1) piece of the cantilever covering over an area of a wide region, then the abrasion of the cantilever proceeds very quickly, and therefore, for the purpose of preventing it, there is already known a technology, as is described in the following Patent Document 2, for example. Thus, a probe (i.e., the cantilever), a W (Write)/R (Read) circuit, a prove driver circuit and a positioning circuit, etc., are formed in one body, in the form of a probe cell, through a monolithic semiconductor process, and the cells are provided in large numbers thereof (for example, 100,000 pieces) for each one of the memory devices. Provision of the large numbers of cells, in this manner, increases up an amount of the information of read-out or write-in, remarkably, per a unit of time, as well as, reducing the traveling distance when reading and writing per one (1) piece of the probe; thereby, enabling to reduce the abrasion of the probes (i.e., the cantilevers) and obtaining a long life-time of the apparatus as a whole.
Patent Document 1: Japanese Patent Laying-Open No. Hei 9-120593 (1997)
Patent Document 2: Japanese Patent Laying-Open No. Hei 8-115600 (1996)
However, in case of the conventional art, as is described in the Patent Document 1 mentioned above (i.e., Japanese Patent Laying-Open No. Hei 9-120593 (1997)), the voltage must be equal or greater than a certain level thereof for achieving the read-in, in particular, when detecting the amount of change of the electric charge, the electrostatic charge or the surface potential, or alternately the differentiated amount of change thereof, under the condition that the stylus-like electrode head is in non-contact with the recording medium, with an aid of a frequency change that is caused at the time when the cantilever is vibrated while applying voltage between the cantilever and the recording medium; however, sufficient consideration is not paid, in particular upon a possibility that the discharge phenomenon occurs from the tip of cantilever to the recording medium at that time, because of being in non-contact therewith, on the contrary thereto, and thereby generating breakdown at the tip of the cantilever, or on the surface of the recording medium; i.e., reducing the reliability thereof. And also, since the cantilever is an electrode of the stylus-like shape, the tip of the cantilever is in contact with the recording medium at a point (i.e., a point contact); therefore, there is another problem that the abrasion can advance, easily.
Also, in case of the conventional art, as is described in the Patent Document 2 mentioned above (i.e., Japanese Patent Laying-Open No. Hei 8-115600 (1996)), with the probe cells, in each of which the probe (i.e., the cantilever) is formed with the W/R circuit, the probe driver circuit and the positioning circuit, etc., corresponding thereto, in one body as a probe cell, it is possible to reduce ill influences due to noises, because stray capacity of wirings can be made small; however, on the other hand thereof, because all of the probe cells must include therein, the W/R circuit, the probe driver circuit and the positioning circuit, etc., then the electric power necessary for all of the probe cells also increases in proportion to the number of those probe cells; i.e., there is a necessity of electric power of a very large amount or quantity thereof. This may results in a possibility of causing a very important obstacle thereto, in particular, when taking a tendency of energy saving and/or mobilization of the apparatus as a whole into the consideration.